Alexander C M, Chen L, Ray R, Marshall B E
Anesthesiology. 1985 Feb;62(2):135-40. doi: 10.1097/00000542-198502000-00007.
The effects of halothane and isoflurane on hypocapnic increases in pulmonary collateral resistance were studied in dogs. A bronchoscope with a double lumen catheter in the suction port obstructed a peripheral airway and allowed gas to flow out of the isolated segment of lung only via collateral channels. The collateral gas flow (Vcoll) was measured with a flowmeter and delivered through one lumen of the catheter, while the other lumen measured distal pressure (Pb). At FRC, the resistance to collateral ventilation (Rcoll) was calculated as Rcoll = Pb/Vcoll. The rest of the lung was ventilated with air, while air (hypocapnia), 10% CO2 in air, or air and halothane or isoflurane were delivered to the isolated segment. A measurement of resistance was made after 4 min of test gas flow. For each segment, when air replaced 10% CO2, the average increase in Rcoll was calculated and called Rmax. When 10% CO2 in air was infused into segments the mean Rcoll (n = 50) was 0.0196 +/- 0.0022 cmH2O X ml-1 X min. This increased to 0.0285 +/- 0.0031 cmH2O X ml-1 X min (mean +/- E) when air was infused, a mean increase in resistance of 52 +/- 3%. When halothane or isoflurane was added to air the hypocapnic increase in Rcoll was attenuated with a 50% decrease at 1.3% (1.4 MAC and 0.8 MAC, respectively). These two inhalational anesthetics reduce active changes in the flow resistance to collateral ventilation. When collateral resistance acts to adjust ventilation perfusion deviations, this action of halothane and isoflurane may make this regulation less effective.
研究了氟烷和异氟烷对犬低碳酸血症时肺侧支循环阻力增加的影响。带有双腔导管的支气管镜置于吸引口，阻塞一条外周气道，使气体仅通过侧支通道从孤立的肺段流出。用流量计测量侧支气流（Vcoll），并通过导管的一个腔输送，而另一个腔测量远端压力（Pb）。在功能残气量（FRC）时，侧支通气阻力（Rcoll）计算为Rcoll = Pb/Vcoll。肺的其余部分用空气通气，而将空气（低碳酸血症）、含10%二氧化碳的空气或空气与氟烷或异氟烷输送至孤立的肺段。在试验气流4分钟后进行阻力测量。对于每个肺段，当空气替代10%二氧化碳时，计算Rcoll的平均增加量并称为Rmax。当向肺段注入含10%二氧化碳的空气时，平均Rcoll（n = 50）为0.0196 +/- 0.0022 cmH2O·ml-1·min。当注入空气时，这一数值增加到0.0285 +/- 0.0031 cmH2O·ml-1·min（平均值 +/- 标准误），阻力平均增加52 +/- 3%。当向空气中添加氟烷或异氟烷时，低碳酸血症时Rcoll的增加减弱，在1.3%（分别为1.4 MAC和0.8 MAC）时降低50%。这两种吸入麻醉药减少了侧支通气气流阻力的主动变化。当侧支阻力用于调节通气灌注偏差时，氟烷和异氟烷的这一作用可能会使这种调节效果降低。
